Island



(No Model.)

J. A. MILLER.

THBRMOSTA'I'.

l fe. 340,890. Patented Apr. 27, 1886.

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UNITED STATES PATENT OFFICE.

JOSEPH A. MILLER, OF PROVIDENCE, RHODE ISLAND.

THERMOSTAT.

GFECZFICAIEGN forming part of Letters Patent No. 340,890, dated April 27, 1886.

Application filed April 23, 1885.

To CLZZ whom it may concern.-

Be it known that l", J OSEPII A. MILLER, of the city and county of Providence, and State of Rhode Island, haveinvented a new and useful Improvcmentin Thermostats, of which the following is a full, clear, and exact description, reference being 11 ad to the accompanying drawings, forming a part of this specification.

My invention relates to thatpclass of devices which are designed to sound an alarm by means of electricity in the event of fire, or when the temperature rises from any cause abovea predetermined limit.

The object of my invention is to insure a positive and distinct alarm in case of fire or the rise of temperature beyond the determined limits, which cannot be mistaken, and which cannot be affected by short-circniting of the circuits, breaking of the lines, grounding, or other derangements,which will also transmit signals differing from the signal caused by the rise of temperature caused by a fire, or from other causes for the detection of which the thermostat is used.

Thermostats as heretofore constructed opened or closed one circuit, and in most cases closed the circuit when the temperature rose to the determined degree. \Vith such thermostats all and every derangement of.the circuit transmitted an alarm, and it is exceedingly difficult to distinguish the signals so as to accurately determine the cause of the disturbance.

My improved thermostat differs from all others, in that one circuit is at all times closed and all. signals are transmitted by this closed circuit, while only a rise of temperature sufficient to break the closed circuit will allow the other circuit to be closed and a distinct alarmsignal to be transmitted.

To the above purpose my invention consists in a thermostat constructed to operate through both an open and a closed circuit; and my invention further consists in certain peculiar and novel details of construction and arrangement, as hereinafter described and claimed.

In order that my invention may be fully understood, I will proceed to describe it with reference to the accompanying drawings, in which- Figure 1 is an upper side plan view of my improved thermostat. Fig. 2 is asimilar view Serial No. 163, 115.

(N0 model.)

of the same, the cap being removed and the shell being partially broken away to expose the internal parts. Fig. 3 is an under side plan view of the same. Fig. 4. is a sectional "low of the same on the line 4 ti of Fig. I. Fig. 5 is a similar view of the same on the line 5 5 of Fig. 1.

In thesaid drawings, A designates the frame or backing of the thermostat, said frame being formed with the extensions a a a a, and composed ofany suitable non-conducting material.

B designates a cup shaped shell, mounted, concave face down, upon frame A. This shell may be of metal, and is formed with an open top, the inner edge having two or more notches, b.

O designates a cap, which is of such form and size as to cover the opening in the shell B, and to the under side of which are secured projections 0, adapted to enter the notches b of the shell. These projections are secured to the cap by asolder fusible at a low tempera ture. Upon cap C is also placed a button, 0, and the arrangement is such that when the cap is to be placed upon the shell the projections c are carried into the notches Z), and then a slight turn is given to the cap, so as to bring the projections c beneath the margin of shell 13, whereby the projections are caused to hold the cap to the shell under normal conditions. \Vhen, however, the temperature rises above a certain predetermined degree, the solder will melt and the lugs will no longer hold the cap.

Upon the extensions a are mounted four binding-posts, d d d" 12", carrying at their up per ends the usual binding-screws, and at their lower ends screws extending upward into the posts through holes in the corresponding extensions, a.

Upon the inner side of frame A is placed a f, extending upward through frame A, a space being left between the upper end of screw f and the under side of the inner end, e, of arm 6, as shown in Fig. 5.

h designates a metallic spring-arm, the inner end, h, of which is bent upward, so as to come into contact with cap 0 when the latter is secured to shell B. At its outer end arm'h is secured to frame A by a metal screw, h", from the lower end of which runs a wire, 9', to the lower screw of binding-post d. The arm h extends between the upper end of screw f and the under side of the inner end, e, of arm 0. A wire, 9 extends from the lower screw of post (I to the lower screw of post d, making contact also with scrcwf. Wires 2' i i i extend, respectively, from the posts (I d d d. The spring-arm h carries an insulator, 76*, upon its outer end, for the purpose of preventing electrical contact between the arm and cap 0. In the normal condition of this thermostat the arm h is pressed down into contact with the upper end ofscrewf by cap O,'and the current flows through wire 'i, post [1, wire arm h, screw f, wire 9, and posts d (l to wires 1' i and thence to line. This is a closed circuit, and if any damage or accident happens to the line an alarm will be given upon one or more annunciators in the system. In case a fire breaks out in the vicinity of the thermostat the solder which holds the projections 0 upon cap 0 will be melted, and said cap will be thrown off by the pressure of spring-arm h, and

at the same time said arm will move out of,

contact with screw f and into contact with arm 0. In this event the current will flow through wire i, post (1, wire 9, arms h and 0, wire 9, post d", and wire 1" to line. An alarm will consequently be given upon the annunciator or annunciators of the system. Thus it will be seen that this thermostat operates two kinds of circuits, one being normally a closed circuit, the breaking of which from any cause will sound an alarm, and the other normally an open circuit, the closing of which by the thermostat will also sound an alarm.

The device is extremely simple and durable, and is certain in its action. Either-wire i or 1' extends to other thermostats to complete the system, or to the battery where but one thermostat is used in a system. a

It is evident that bot-h circuits may be closed circuits, so that a different signal. is trans mitted when the circuit-closer, which is in this case the arm h, moves from the contactpoint at the end of screw f and comesin contact with the contact-point at the end of arm (2..

Fig. 5 shows the action of the thermostat. The solder being melted, the arm h is throw-n out of contact with f, thereby breaking the normally-closed circuit, and the arm h coming in contact with e, thereby closing the nor-' Having thus described my invention, I claim as new and desire to secure by Letters Patent- 1. The combination of two independent main circuits, one normally closed and the other normally open, with a thermostatic device breaking the normally-closed circuit and closing the normally-open circuit upon a sufficient rise of temperature, as specified.

2. In combination, a normally-closed and a normallyopen circuit and a thermostat having a rigid and a resilient arm, said resilient arm, when depressed, preserving the continuity of the said closed circuit, and -when released breaking this circuit and closing the said open circuit by contact with said rigid 4. The combinatiomwith the frame A, havv ing the extensions a, the shell B, having the notches b, and the cap 0, having the projections c secured to it by fusible solder, of the binding-posts d d (1 d the screws f e h the wires 1' t" t" i g gg, the arm e, having bent end 6, and the arm h, having bent end h, as and for the purposes set forth.

5. In combination, two independent main circuits and a thermostat normally preserving the continuity of one circuit, and upon a sutficient rise of temperature breaking this circuit and closing the normally-open circuit to send an alarm-signal, as specified.

6. In combination, two main circuits, one

circuit and establishing the continuity of the other upon an increase of temperature, as de' scribed.

In witness whereof I have hereunto set my hand.

JOSEPH A. MILLER. Witnesses:

M. F. BLIGH, J. A. MILLER, Jr. 

